Occurs when the Control modifier key (CTRL) and C console key (C) are pressed simultaneously (CTRL+C).
Namespace:
System
Assembly:
mscorlib (in mscorlib.dll)
Visual Basic (Declaration)
Public Shared Event CancelKeyPress As ConsoleCancelEventHandler
Dim handler As ConsoleCancelEventHandler
AddHandler Console.CancelKeyPress, handler
public static event ConsoleCancelEventHandler CancelKeyPress
public:
static event ConsoleCancelEventHandler^ CancelKeyPress {
void add (ConsoleCancelEventHandler^ value);
void remove (ConsoleCancelEventHandler^ value);
}
JScript does not support events.
This event is used in conjunction with System..::.ConsoleCancelEventHandler and System..::.ConsoleCancelEventArgs. The CancelKeyPress event enables a console application to intercept the CTRL+C signal so the application can decide whether to continue executing or terminate. For more information about handling events, see Consuming Events.
Use this event to explicitly control how your application responds to the CTRL+C signal. If your application has simple requirements, you can use the TreatControlCAsInput property instead of this event.
The event handler for this event is executed on a thread pool thread.
The following code example demonstrates how the CancelKeyPress event is used.
' This example demonstrates:
' the Console.CancelKeyPress event,
' the ConsoleCancelEventHandler delegate,
' the ConsoleCancelEventArgs.SpecialKey property, and
' the ConsoleCancelEventArgs.Cancel property.
Imports System
Class Sample
Public Shared Sub Main()
Dim cki As ConsoleKeyInfo
' Clear the screen.
Console.Clear()
' Turn off the default system behavior when CTRL+C is pressed. When
' Console.TreatControlCAsInput is false, CTRL+C is treated as an
' interrupt instead of as input.
Console.TreatControlCAsInput = False
' Establish an event handler to process key press events.
AddHandler Console.CancelKeyPress, AddressOf myHandler
While True
' Prompt the user.
Console.Write("Press any key, or 'X' to quit, or ")
Console.WriteLine("CTRL+C to interrupt the read operation:")
' Start a console read operation. Do not display the input.
cki = Console.ReadKey(True)
' Announce the name of the key that was pressed .
Console.WriteLine(" Key pressed: {0}" & vbCrLf, cki.Key)
' Exit if the user pressed the 'X' key.
If cki.Key = ConsoleKey.X Then Exit While
End While
End Sub 'Main
' When you press CTRL+C, the read operation is interrupted and the
' console cancel event handler, myHandler, is invoked. Upon entry
' to the event handler, the Cancel property is false, which means
' the current process will terminate when the event handler terminates.
' However, the event handler sets the Cancel property to true, which
' means the process will not terminate and the read operation will resume.
Protected Shared Sub myHandler(ByVal sender As Object, _
ByVal args As ConsoleCancelEventArgs)
' Announce that the event handler has been invoked.
Console.WriteLine(vbCrLf & "The read operation has been interrupted.")
' Announce which key combination was pressed.
Console.WriteLine(" Key pressed: {0}", args.SpecialKey)
' Announce the initial value of the Cancel property.
Console.WriteLine(" Cancel property: {0}", args.Cancel)
' Set the Cancel property to true to prevent the process from terminating.
Console.WriteLine("Setting the Cancel property to true...")
args.Cancel = True
' Announce the new value of the Cancel property.
Console.WriteLine(" Cancel property: {0}", args.Cancel)
Console.WriteLine("The read operation will resume..." & vbCrLf)
End Sub 'myHandler
End Class 'Sample
'
'This code example produces results similar to the following text:
'
'Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
' Key pressed: J
'
'Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
' Key pressed: Enter
'
'Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
'
'The read operation has been interrupted.
' Key pressed: ControlC
' Cancel property: False
'Setting the Cancel property to true...
' Cancel property: True
'The read operation will resume...
'
' Key pressed: Q
'
'Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
' Key pressed: X
'
// This example demonstrates:
// the Console.CancelKeyPress event,
// the ConsoleCancelEventHandler delegate,
// the ConsoleCancelEventArgs.SpecialKey property, and
// the ConsoleCancelEventArgs.Cancel property.
using System;
class Sample
{
public static void Main()
{
ConsoleKeyInfo cki;
// Clear the screen.
Console.Clear();
// Turn off the default system behavior when CTRL+C is pressed. When
// Console.TreatControlCAsInput is false, CTRL+C is treated as an
// interrupt instead of as input.
Console.TreatControlCAsInput = false;
// Establish an event handler to process key press events.
Console.CancelKeyPress += new ConsoleCancelEventHandler(myHandler);
while (true)
{
// Prompt the user.
Console.Write("Press any key, or 'X' to quit, or ");
Console.WriteLine("CTRL+C to interrupt the read operation:");
// Start a console read operation. Do not display the input.
cki = Console.ReadKey(true);
// Announce the name of the key that was pressed .
Console.WriteLine(" Key pressed: {0}\n", cki.Key);
// Exit if the user pressed the 'X' key.
if (cki.Key == ConsoleKey.X) break;
}
}
/*
When you press CTRL+C, the read operation is interrupted and the
console cancel event handler, myHandler, is invoked. Upon entry
to the event handler, the Cancel property is false, which means
the current process will terminate when the event handler terminates.
However, the event handler sets the Cancel property to true, which
means the process will not terminate and the read operation will resume.
*/
protected static void myHandler(object sender, ConsoleCancelEventArgs args)
{
// Announce that the event handler has been invoked.
Console.WriteLine("\nThe read operation has been interrupted.");
// Announce which key combination was pressed.
Console.WriteLine(" Key pressed: {0}", args.SpecialKey);
// Announce the initial value of the Cancel property.
Console.WriteLine(" Cancel property: {0}", args.Cancel);
// Set the Cancel property to true to prevent the process from terminating.
Console.WriteLine("Setting the Cancel property to true...");
args.Cancel = true;
// Announce the new value of the Cancel property.
Console.WriteLine(" Cancel property: {0}", args.Cancel);
Console.WriteLine("The read operation will resume...\n");
}
}
/*
This code example produces results similar to the following text:
Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
Key pressed: J
Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
Key pressed: Enter
Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
The read operation has been interrupted.
Key pressed: ControlC
Cancel property: False
Setting the Cancel property to true...
Cancel property: True
The read operation will resume...
Key pressed: Q
Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
Key pressed: X
*/
// This example demonstrates:
// the Console.CancelKeyPress event,
// the ConsoleCancelEventHandler delegate,
// the ConsoleCancelEventArgs.SpecialKey property, and
// the ConsoleCancelEventArgs.Cancel property.
using namespace System;
// When you press CTRL+C, the read operation is interrupted and the
// console cancel event handler, myHandler, is invoked. Upon entry
// to the event handler, the Cancel property is false, which means
// the current process will terminate when the event handler terminates.
// However, the event handler sets the Cancel property to true, which
// means the process will not terminate and the read operation will resume.
void OnCancelKeyPressed(Object^ sender,
ConsoleCancelEventArgs^ args)
{
// Announce that the event handler has been invoked.
Console::WriteLine("{0}The read operation has been interrupted.",
Environment::NewLine);
// Announce which key combination was pressed.
Console::WriteLine(" Key pressed: {0}", args->SpecialKey);
// Announce the initial value of the Cancel property.
Console::WriteLine(" Cancel property: {0}", args->Cancel);
// Set the Cancel property to true to prevent the process from
// terminating.
Console::WriteLine("Setting the Cancel property to true...");
args->Cancel = true;
// Announce the new value of the Cancel property.
Console::WriteLine(" Cancel property: {0}", args->Cancel);
Console::WriteLine("The read operation will resume...{0}",
Environment::NewLine);
}
int main()
{
// Clear the screen.
Console::Clear();
// Turn off the default system behavior when CTRL+C is pressed. When
// Console.TreatControlCAsInput is false, CTRL+C is treated as an
// interrupt instead of as input.
Console::TreatControlCAsInput = false;
// Establish an event handler to process key press events.
Console::CancelKeyPress +=
gcnew ConsoleCancelEventHandler(OnCancelKeyPressed);
while (true)
{
// Prompt the user.
Console::Write("Press any key, or 'X' to quit, or ");
Console::WriteLine("CTRL+C to interrupt the read operation:");
// Start a console read operation. Do not display the input.
ConsoleKeyInfo^ keyInfo = Console::ReadKey(true);
// Announce the name of the key that was pressed .
Console::WriteLine(" Key pressed: {0}{1}", keyInfo->Key,
Environment::NewLine);
// Exit if the user pressed the 'X' key.
if (keyInfo->Key == ConsoleKey::X)
{
break;
}
}
}
/*
This code example produces results similar to the following text:
Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
Key pressed: J
Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
Key pressed: Enter
Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
The read operation has been interrupted.
Key pressed: ControlC
Cancel property: False
Setting the Cancel property to true...
Cancel property: True
The read operation will resume...
Key pressed: Q
Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
Key pressed: X
*/
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0, 2.0
Reference